Reversible gravity mixer for concrete and mortar



P. AUGUST Aug. 25, 1964 REVERSIBLE GRAVITY MIXER FOR CONCRETE AND MORTAR Filed Aug. 26, 1963 United States PatentO 3,145,977 REVERSIBLE GRAVITY MIXER FOR CONCRETE AND MURTAR Paul August, Lavalle 6S2, Buenos Aires, Argentina Filed Aug. 26, 1963, Ser. No. 304,332 9 Claims. (Cl. 259-163) My present invention refers to certain new and useful improvements in reversible gravity mixers for the production of concrete, mortar and the like.

The modern reversible gravity mixers are provided with two driving motors and with a push button control. One of these motors drives the mixing drum, whereas the second motor operates a tub lift for charging the mixing drum. The provision of the two motors and of the push button control for the two motors is rather expensive and considerably increases the cost of manufacture of the mixers.

The invention aims at reducing the cost of manufacture by simplifying the construction of the mixers referred to without renouncing to the push button control, insofar as but one driving motor is required and as the manner of supporting the mixing drum is improved with the advantageous result that the whole driving mechanism of the mixer is technically very simple and consequently economical;

The main object of the invention is to provide an improved reversible gravity mixer, comprising a reversible mixing drum for discharging its contents by rotating in a direction opposite the direction of rotation of the mixing process, and a tub lift for charging said mixing drum, characterized in that not only for the operation of the mixing drum in one and the other direction of rotation, but also for the operations of the tub lift there is provided one driving motor only and a rope drum of the winch of said tub lift comprises a freewheel hub for connecting said winch of said tub lift with said driving motor 'during its operation in one direction only.

The driving motor of the mixer conveniently is a geared electric motor. The control of this motor is realized by means of a push button system conveniently in combination 'with a switch which is automatically operated by the tub of said tub lift in its upper position.

According to an additional feature of the invention, the mixing drum at its rear end has a flange portion forming a pulley for the belt of the transmission which operatively connects the driving motor with said mixing drum. g

In accordance with still another feature of the invention, the mixing drum is supported near itsfront end in a known manner by loose rollers and at its rear end by means of a shaft which is mounted in a bearing arranged outside the mixing drum and capable of fixing said drum against axial displacement, said shaft being arranged coaxially with the drum axis.

Further characteristic and advantageous features of the mixer will be appreciated from the following description of a preferred embodiment of the invention as shown on the accompanying drawing in a schematic partly sectioned side elevation.

The accompanying drawing shows a movable gravity mixer, comprising a mixing drum 1, a chassis 2, guide rails 3 for the tub 4 of a tub lift. Near its front end the mixing drum 1 is supported in a known manner by a pair of loose rollers 5 arranged at both sides on the frame of the chassis 2. At its rear end, however, the mixing drum is mounted by means of a shaft 6 in a bearing 7 outside the drum and is connected with the drum shell by radial arms 20 in a position coaxial with the axis of the drum, said bearing 7 being constructed for fixing the mixing drum against axial displacement.

A geared electric motor 8 drives the mixing drum 1 by 3,145,977 Patented Aug. 25, 1964 "ice there is provided a rope drum 11 comprising a known freewheel hub. A rope or cable 12 fastened on the rope drum 11 is connected to a second rope drum 13, so that the latter is operated by traction. On the shaft 13a of the rope drum 13 there is fixedly mounted a like additional rope drum which does not appear on the drawing for being behind the drum 13 and which is situated substantially opposite the middle of the tub 4, a cable or rope 14- connecting said additional rope drum with the tub 4 of the tub lift, so that coiling, respectively uncoiling of said rope 14, causes the tub to 'move up and downwards, respectively.

For guiding the tub 4 in these movements, the same is provided with two pairs of carrier rollers 16, 16a, of which the rollers 16a are guided in a known manner by the guide rails 3 of U-shaped cross section, whereas the rollers 16 travel along guide members 15. These guide members 15 form part of a hood having side walls 21 shielding the rear end of the mixing drum and its driving mechanism. Within the hood there are two plates 17 and 18 forming a chute for guiding the materials to be mixed and to be delivered by the tub 4 into the mixing drum 1.

The operation of the mixer is a follows:

During the mixing periods the motor 8 rotates in a direction in which the rope drum 11 due to its freewheel hub is not operated and only the drum 1 is caused to rotate so as to perform the mixing operation. During these periods the tub 4 is in its lower position for receiving the materials to be mixed. When the operations of charging the tub and of mixing a batch in the drum are finished, the direction of rotation of the motor 8 is changed by means of a known push button control (not shown), so that now the drum 1 is caused to rotate in 0pposite direction and to effect the discharge of the mixture. During this rotation of the mixer motor 8 the freewheel hub of the rope drum 11 operatively connects into the mixing drum 1.

The operation speed of the tub lift is so elected that the mixing drum will be empty or substantially empty when the tub 4 reaches its upper position. In this moment a switch 19 arranged, for instance, on the upper edge of one side wall 21 and automatically operated by said tub in its upper position disconnected the motor 8 and at the same time changes its direction of rotation so that the drum now starts a new mixing operation.

Conveniently a small brake device is provided in a rope drum 11 or 13, which at the moment the tub 4 reaches its lower position, prevents the cables or ropes 12 and 14 from further uncoiling from the respective rope drums 11 and 13.

As set forth in the preceding description, the present invention provides a modern reversible gravity mixer with push button control, which carries out all the operative steps with but one motor and wherein the supporting and driving means of the mixing drum and of the tub lift are technically very simple and economical.

What I claim is:

1. A reversible gravity mixer for concrete and mortar, comprising a supporting structure, a rotary mixing drum carried by said structure, a pair of loose rollers provided at both sides on said structure for supporting the front end of said mixing drum, bearing means for supporting the rear end of said mixing drum, a tub lift for charging said mixing drum, a driving motor operatively connected with said mixing drum for operating the latter alternately in one and the other direction for mixing its charge, respectively for discharging its contents, and with said tub lift for hoisting the tub of this lift during the discharging rotation of said mixing drum, the operative connection between said motor and said tub including rope drums and ropes and one of these rope drums including a known freewheel hub.

2. A reversible gravity mixer for concrete and mortar, comprising a supporting structure, a rotary mixing drum carried by said structure, a pair of loose rollers provided at both sides on said structure for supporting the front end of said mixing drum, bearing means for supporting the rear end of said mixing drum, a tub lift for charging said mixing drum, an electric geared motor operatively connected with said mixing drum for operating the latter alternately in one and the other direction for mixing its charge, respectively for discharging its contents, and with said tub lift for hoisting the tub of this lift during the discharging operation of said mixing drum, the operative connection between said motor and said tub including rope drums and ropes and one of these rope drums including a known freewheel hub.

3. A reversible gravity mixer for concrete and mortar, comprising a supporting structure, a rotary mixing drum carried by said structure, a pair of loose rollers provided at both sides on said structure for supporting the front end of said mixing drum, bearing means for supporting the rear end of said mixing drum, a tub lift for charging said mixing drum, an electric geared motor operatively connected with said mixing drum for operating the latter alternately in one and the other direction for mixing its charge, respectively for discharging its contents, and with said tub lift for hoisting the tub of this lift during the discharging rotation of said mixing drum, the operative connection between said motor and said drum and said tub comprising a V-belt transmission of which the pulley of said mixing drum is formed by a flange portion of the latter, respectively rope drums and ropes, and one of these rope drums including a known freewheel hub.

4. A reversible gravity mixer for concrete and mortar as set forth in claim 3, wherein the said pulleys are flat belt pulleys.

5. A reversible gravity mixer for concrete and mortar, comprising a supporting structure, a rotary mixing drum carried by said structure, a pair of loose rollers provided at both sides on said structure for supporting the front end of said mixing drum, a shaft projecting from the rear end of said mixing drum, a bearing for supporting the free end of said shaft, a tub lift for charging said mixing drum, an electric geared motor operatively connected with said mixing drum for operating the latter alternately in one and the other direction for mixing its charge, respectively for discharging its contents, and with said tub lift for hoisting the tub of this lift during the discharging rotation of the mixing drum, the operative connections between said motor and said drum and said tub comprising a V-belt transmission of which the pulley of said mixing drum is formed by a flange portion of the latter, respectively rope drums and ropes, and one of these rope drums including a known freewheel hub.

6. A reversible gravity mixer for concrete and mortar as set forth in claim 5, wherein the said bearing is a thrust-absorbing bearing capable of fixing said shaft and said mixing drum against axial displacements.

7. A reversible gravity mixer for concrete and mortar comprising a supporting structure, a rotary mixing drum carried by said structure, a pair of loose rollers provided at both sides on said structure for supporting the front end of said mixing drum, a shaft projecting from the rear end of said mixing drum, a bearing for supporting the free end of said shaft, a tub lift for charging said mixing drum, the tub of this lift comprising two pairs of loose carrier rollers, guide rails for one pair of these rollers and guide means for the second pair of these rollers, these guide means being formed by edges of a hood shielding the rear end of the mixer, an electric geared motor operatively connected with said mixing drum for operating the latter alternately in one and the other direction for mixing its charge, respectively for discharging its contents, and with said tub lift for hoisting the tub of this lift during the discharging rotation of the mixing drum, the operative connections between said motor and said drum and said tub comprising a V-belt transmission of which the pulley of said mixing drum is formed by a flange portion of the latter, respectively rope drums and ropes, and one of these rope drums including a freewheel hub.

8. A reversible gravity mixer as set forth in claim 7, wherein within the said hood a chute is provided for guiding the materials to be mixed into the said mixing drum.

9. A reversible gravity mixer according to claim 1, wherein the said operative connections between the said driving motor and the said mixing drum and the tub of the said tub lift are arranged for substantially equal time periods required for the discharge of said mixing drum and for the upward movement of said lift tub.

References Cited in the tile of this patent UNITED STATES PATENTS 1,760,101 Yohe May 27, 1930 

1. A REVERSIBLE GRAVITY MIXER FOR CONCRETE AND MORTAR, COMPRISING A SUPPORTING STRUCTURE, A ROTARY MIXING DRUM CARRIED BY SAID STRUCTURE, A PAIR OF LOOSE ROLLERS PROVIDED AT BOTH SIDES ON SAID STRUCTURE FOR SUPPORTING THE FRONT END OF SAID MIXING DRUM, BEARING MEANS FOR SUPPORTING THE REAR END OF SAID MIXING DRUM, A TUB LIFT FOR CHARGING SAID MIXING DRUM, A DRIVING MOTOR OPERATIVELY CONNECTED WITH SAID MIXING DRUM FOR OPERATING THE LATTER ALTERNATELY IN ONE AND THE OTHER DIRECTION FOR MIXING ITS CHARGE, RESPECTIVELY FOR DISCHARGING ITS CONTENTS, AND WITH SAID TUB LIFT FOR HOISTING THE TUB OF THIS LIFT DURING THE DISCHARGING ROTATION OF SAID MIXING DRUM, THE OPERATIVE CONNECTION BETWEEN SAID MOTOR AND SAID TUB INCLUDING ROPE DRUMS AND ROPES AND ONE OF THESE ROPE DRUMS INCLUDING A KNOWN FREEWHEEL HUB. 